When your co-worker comes bursting through the back door and says "I just saw a fox run across the field.", and you just happen to have your good camera with you... well you run out the door (quietly) and go stalking a fox.
I had not been able to find this one. He ran when I accidentally flushed him from the grass.
If you look closely, you can see what appears to be a Richardson's Ground Squirrel in its mouth.